During operation of internal combustion engines, the hot surfaces of the components can be exposed to many gases and liquids including the fuel composition, lubricating fluids, combustion byproducts, and so forth. If undesirable deposits or sludge forms on such components as a result of this operation, the engine performance can be negatively affected. For example, deposits on fuel injectors can undesirably obstruct or plug metering holes of the injector tip. Likewise, deposits on intake valves can reduce optimal engine performance.
Accordingly, as the fuel composition can affect the level of such deposit formation or fouling, much effort continues to be put forth in the industry in an attempt to develop fuel composition detergent additives capable of controlling, reducing, or eliminating such fouling formation.
However, in order to test the effectiveness of such detergent additives for fuel compositions, repeatable deposit build-up reference fuel compositions are needed. A reference fuel composition is a fuel composition that repeatedly and consistently can create deposits in an engine during testing. This is sometimes referred to as “dirty-up” fuel in the industry. The effectiveness of various detergent additives added to the reference fuel composition to reduce deposits can then be evaluated, compared, and optimized. Moreover, having a consistent carbon deposit producing “dirty-up” reference fuel composition also can advantageously enable the evaluation of new engine hardware components and calibration systems. Also, in recent years, several automobile manufacturers jointly created a voluntary deposit control standard for gasoline with a goal to define a new class of commercial gasoline with enhanced detergency termed TOP TIER Detergent Gasoline. Thus, the TOP TIER Detergent Gasoline program also would benefit from the development of such consistent reference fuel compositions.
Accordingly, it is desirable to provide a reference fuel composition useful for, for example, evaluating gasoline detergent additives and/or engine hardware.